Arrangement for call control in two-way systems with selector installation



Aug. 1, 1950 2,517,259

Q. TSCHUM! ARRANGEMENT FOR CALL CONTROL IN TWO-WAY SYSTEMS WITH SELECTORINSTALLATION Filed Jan. 20, 19455 l' vezzr r 0.2 56214 Patented Aug. 1,1950 ARRANGEMENT FOR CALL CONTROL IN TWO-WAY SYSTEMS WITH SELECTORINSTALLATION Otto 'Ischumi, Soleure, Switzerland, assignor to the firmAutophon Aktiengesellschaft, Soleure, Switzerland, a joint-stock companyof Switzerland Application January 20, 1945, Serial No. 573,692 InSwitzerland December 31, 1943 2 Claims.

The invention relates to arrangements for call control in two-waysystems with selector installation. In two-way systems of this kind,besides the real selector means, a switch means for changing-over thespeaking direction must be provided. This accumulation of switch devicesin a subscribers station renders the service dinicult and the wholesubscribers device complicated.

In the arrangement according to the invention a simplification isobtained in that the two switch means are united in a single meanscarrying out both operations. It i characterised in that the selectormeans serves simultaneously for controlling the speaking direction.

Usually, a key arrangement is chosen wherein a main key (in oppositionto a release key) can, by depressing, be brought into two differentpositions, one of these latter being a holding position. In this latter,line contacts corresponding to the key are operated, while in the otherdirection the control contacts carry out the changeover of the speakingdirection.

The accompanying drawing illustrates, by way of example, one embodimentof the object of invention in which the single selector means is formedas a key.

Figs. 1 to 3 show schematically the different positions of a switchmeans formed as a key operating both as selector and as change-overswitch for the speaking direction.

T is a key forming the universal switch means, Hs is a holding pin, andN a key-nose. Ab is a lock bar, As a stop pin, Fl and F2 draw springs, Othe pivot of the key T and 00. that of the lock bar Ab. AT designatesthe release key connected by means of the bent lever K, rotatable about0, with the lock bar Ab over a rod. Ks is the control contact forcontrolling the speaking direction and Kl the line contact forestablishing a connection with the line in question.

Fig. 1 shows the rest position. The position of the contact Kscorresponds to a certain operating condition, for instance to listening.The line contacts Kl are open, no connection is established with theline in question. If, as is shown in Fig. 2, the key is depressed andthereby brought into holding position, the lock bar Ab falls under theholding pin I-Is where it is held owing to the traction of the springFl. This has as a consequence that, the operating condition of thecontrol contacts Ks remaining the same (listening), the line contacts KZare closed. If the speaking direction is now to be changed, that is if,in this example, the operating condition speaking is to be established,the key T is further depressed.

This position of the key T, which is represented in Fig. 3, is however,not a holding position, but the key T, under the influence of the springF2 has a tendency to take again the first position. A short-periodoperation of the key beyond the former position is, therefore, equal toa similar short-period operation of the control contact Ks which ismoved by the nose N. This short-period operation corresponds exactly tothe impulse necessary for changing the speaking direction (see forinstance application Serial No. 535,297, now Patent No. 2,460,475,granted February 1, 1949). From the aforesaid it may be seen that by acomplete short-period depression of the selector means it is possible tochange the speaking direction at will.

If the connection with the line in question is to be interrupted and thekey to be returned into initial position, any suitable mechanical meansis to be operated annulling the locking effect of the spring FI and ofthe locking bar Ab. In the example illustrated this means consists ofthe release key AT, the depression of which is transmitted to the lockbar Ab over the bent lever K, putting the lock bar Ab out of reach ofthe holding pin H8 and thereby allowing the key T, under the influenceof the return spring F2, again to reach the outgoing position of Fig. l.

A contact Ks sufiices for an entire selector key set in that it can bemechanically connected with all the keys.

In thi way uniting the two switch means in a single one and thereby asimplification of the device is obtained.

What I claim is:

1. In an arrangement of the character described, first and second setsof contacts, a key normally occupying an inoperative position withrespect to both sets of contacts, means whereby said key is moved into aposition to render the first set of contacts operative, means wherebysaid key is effective in a third position to main- REFERENCES CITED Thefollowing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Dumbar Dec. 19, 1911 Kneisly Nov.19, 1912 Gibson Sept. 8, 1914 Koch Mar. 22, 1921 Fox Oct. 9, 1934Johnson June 16, 1936 Frazier Sept. 22, 1936

